/*
 * Copyright 2022 The Project Oak Authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

.section .boot, "ax"
.global _start
.code64

_start:
    # Clear BSS: base address goes to RDI, value goes to AX, count goes into CX.
    mov $bss_start, %rdi
    mov $bss_size, %rcx
    xor %rax, %rax
    rep stosb

    mov $stack_start, %rsp
    # Push 8 bytes to fix stack alignment issue. Because we enter rust64_start
    # with a jmp rather than a call the function prologue means that the stack
    # is no longer 16-byte aligned.
    push $0
    jmp rust64_start
